COVID-19 Variant Supplement – Production of a recombinant S ( spike ) protein vaccine against SARS-CoV-2 and emerging coronaviruses
In December 2019 a human coronavirus (CoV) outbreak causing pneumonia-like symptoms began, centered around a fish market in the Wuhan district of China. After the genomic sequence was determined the causative pathogen, SARS-CoV-2, showed 99.98% identity among 9 patients, was 88% identical to two bat SARS-like CoV, ~79% identical to SARS-CoV, and ~50% identical to MERS-CoV (Tan 2020 Lancet). SARS-CoV and MERS-CoV were responsible for severe human illness and mortality (~10% in 2002 and ~35% in 2013, respectively). Although understanding of SARS-CoV-2 and the COVID‑19 disease is ongoing, it is believed human-to-human transmission is possible and the disease fatality rate is ~2-3%. In early February 2020, WHO reported >31,000 confirmed human infections, >640 deaths, and declared a Public Health Emergency of International Concern, presumably due to the possibility of a pandemic. The coronavirus 2019 outbreak is the third coronavirus outbreak causing a severe human disease in the past ~20 years. Currently a coronavirus prophylaxis vaccine and therapeutic drugs are not available. In this application we describe the investigation of vaccine candidates. Our team has manufacturing experience expressing a subunit Hepatitis-C virus vaccine candidate and has developed methods for industry-scale vaccine purification using removable purification tags (Logan 2017 Journal of Virology). This work will identify a CoV vaccine candidate that can proceed to the creation of a manufacturing grade mammalian cell line.